The present invention relates generally to a method for exterminating pests by thermal treatment of articles which may harbor or provide host opportunities to pests and/or insects, wherein the treatment includes forming a flexible film enclosure about the articles in which the articles undergo exposure to a flow of heated outside air under controlled and isolated conditions. Exposure continues for a period of time sufficient to eradicate or exterminate the pests. The term xe2x80x9cpestsxe2x80x9d is intended to refer generally to creatures such as insects, mammals, reptiles, and the like, but may also include some other undesirable but non-toxic forms of matter such as certain types of bacteria, molds, and viruses.
In the past, various techniques have been employed to exterminate pests, including the exposure to toxic or lethal gases, such as those used in typical fumigation techniques including methyl bromide, dibromobenzene, phosphine, or the like. These techniques involve certain risks to personnel, as well as to the environment, and hence are not readily undertaken without necessary precautions. Some are environmentally unfriendly. On the other hand, the present invention involves a technique for treating the affected articles thermally, with this technique being effective while creating little if any danger to the ambient atmosphere or the environment. Delays resulting from extended periods of post-treatment venting as required with chemical fumigants are also avoided.
As the volume of commerce between individual nations increases, the risk of introduction of new, aboriginal, and/or undesirable pests to the importing nation becomes greater. Introduction of such pests to a nation may occur when the environment of the importing nation lacks a natural enemy for the introduced pest. Accordingly, restrictive regulations are in place in and among trading nations which require proof of pest eradication treatment for the articles being imported, including the actual products as well as auxiliary items such as cargo containers, pallets, and the like. These restrictive regulations make good sense for the importing nation, and strict adherence is, of course, both appropriate and necessary.
In the past it has been common practice to employ certain chemicals and/or fumigants in pest eradication and/or extermination operations. However, because of the adverse affects of popular and traditional fumigants upon humans and the environment, various agencies including environmental protection and pollution control agencies have mandated bans upon use of a number of popular and traditional fumigants. While thermal treatment has been utilized and found to be generally acceptable, traditional thermal treatment operations have proven to be costly, burdensome, and time consuming, and hence are only undertaken with added cost to the seller and/or buyer. The process of the present invention facilitates and expedites thermal treatment of articles so as to substantially reduce the time required for treatment, with a corresponding reduction in cost.
Present thermal treatment operations generally employ a rigid walled chamber, such as a room, compartment or conventional shipping container, the chamber being equipped with a source of heated air, along with one or more exhaust or vent ports. In use, the articles to be treated are introduced into the container, subjected to a thermal treatment cycle, permitted to cool, and thereafter unloaded from the treatment chamber. In accordance with the present invention, however, a thermal treatment process facilitates and expedites portable, rapid and effective thermal eradication and extermination operations.
In preparing articles for processing, the articles to undergo treatment are identified, gathered, and isolated. Articles to be treated are typically, but not always, in the process of being transported from one locale to a new locale, and hence are frequently loaded on pallets, with the pallets, in turn, being loaded upon a transport vehicle such as a flatbed. Due to its portability, the process of the present invention is uniquely adapted for implementation while the articles or objects undergoing the treatment process are permitted to remain on the transport vehicle. In other words, due to the portability of the treatment chamber, it is not necessary to unload or specially stack the articles prior to exposure to the treatment process, thereby substantially reducing the handling steps which would otherwise be necessary. The process of the present invention, utilizing its portability feature, may be employed for treatment of stationary articles such as, for example, food processing equipment. Depending upon the nature of the equipment and/or its ultimate application, it is common practice to treat such equipment periodically so as to eliminate the presence of any pests which the equipment may harbor. The portability feature of the process permits the virtual enveloping of the equipment within a chamber created from flexible heat resistant material such as film or woven cloth, and through which the air heated pursuant to the process of the present invention is passed.
Thus, in accordance with the present invention, a gas impermeable flexible film is employed to create an enclosure which envelops the articles being treated, i.e. the xe2x80x9cworking chargexe2x80x9d. The enclosure is then sealed so as to fully envelop and effectively isolate the working charge. A source of thermal energy is coupled to the enclosure for delivery of a flow of heated air into the enclosure. One or more exhaust vents, as required for the application, are provided in order to move a significant flow of heated air through the film enclosure. The flow of thermal energy is controlled so as to provide an appropriate ramp-up rate followed by a flow to maintain an elevated temperature under steady-state conditions, and thereafter maintaining a flow of ambient air through the enclosure to accomplish cool-down. In order to appropriately monitor the conditions within the enclosure, a number of temperature sensors are placed throughout the enclosure so as to enable the technicians to verify the temperature and thermal conditions throughout the enclosure. Additionally, devices may be provided so as to measure flow rates of air in order to assist in the monitoring.
The gas impermeable flexible film is sealed by means of hook-and-loop fasteners, ratchet tie-downs, and/or other mechanical fasteners such as grommets or other means in order to limit the flow of air through the seam.
The technique of the present invention is adaptable for use in a wide variety of situations. This includes treatment of products which are stacked, situated on shipping pallets, as well as pallets per se, and stationary processing equipment, particularly food processing equipment. The requirements for the articles undergoing or requiring treatment pose few problems or limitations. While it is appropriate that the heat generating equipment be properly sized for the application, the process may be undertaken utilizing conventional fuels including natural gas, propane, steam, electricity, or combinations thereof.
Therefore, it is a primary object of the present invention to provide an improved method, apparatus and system for exterminating pests by thermal treatment of articles which may harbor or provide host opportunities to pests and/or insects, the treatment including formation of a flexible enclosure of heat resistant material about the articles, and thereafter exposing the articles within the enclosure to a flow of heated outside air under controlled and isolated conditions.
It is a further object of the present invention to provide an improved thermal treatment for pest-harboring articles wherein an inflatable enclosure is created about a group of articles to be treated, and thereafter causing a flow of heated air to pass through the enclosure, with the temperature within the enclosure being continuously monitored in accordance with a predetermined thermal cycle.
Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and accompanying drawings.